Boiling fuel solutions
 

Good afternoon all,


So I've corrected one issue on my Plymouth, only to find another. This weekend was pretty warm here in the hi-desert (upper 90's), and after a bit of driving I wasn't able to start the car up. I had gone into a store, came back out and found that fuel was boiling up and out of the carb's airhorn, and that the temp gauge was well to the right, even though it tends to stay in the center or just right of center during most driving.


I assume the temp gauge reading is just from the engine sitting and coolant not being circulated by the pump and cooled, but what can I do to prevent the carb from retaining so much heat and boiling fuel off? It's barely into Spring here in Southern California, and the Summer months are much hotter throughout the day in 29 Palms, so I need to find a solution or I won't be able to drive much. Thanks for any input!

is it stock? what mods? surely it doesn't have copper fuel lines? is the first place to start.

Good to see you checked in... Glad to hear you and the guys got the 54 all up and running....... Try to find a thick carb to manifold gasket... The will help... Also lower the fuel level just a tad....
Make sure the fins are good and st right.. Make sure the fan is just inside the fan shroud.. Belt not slipping at road speed.... Right Blade fan> 6 or 7 blade??? Pick up some Water Wetter....

Moe..... >>>>>
https://moparforums.com/forums/f88/1...alms-ca-18363/

:)

Thicker gasket or maybe even a small phenolic spacer. This will help keep the heat transfer from the intake to the carb to a minimum. Make sure all your fuel lines are away from any heat sources (manifolds, exhaust, etc.).

So I've found single-barrel phenolic spacers on eBay, but I'm not in California at the moment and I have no idea what the bore size/bolt spacing is for the Carter carbs that came on the flathead six. Does anyone know the bore/bolt spacing?

Modern fuel is oxygenated and it has a lower boiling point than the old stuff.

Ive seen this on small block Mopars, Cadillac, and Packard.

The only real solution as far as I can see is to install an electric fuel pump back at the tank and plumbed inline as a backup to the mechanical pump. Then when the fuel to boils over after a hot drive, run the electric fuel pump for 15 seconds before you start the engine.

You will also need to install a one way check valve in the fuel line that bypasses the fuel pump so that when the electric pump is running that the outflow from the electric pump does not follow the path of least resistance and go right back to the electric pump intake. Most fuel pump kits will have this check valve.

It's a problem!!! I eventually went to EFI, but that 's a long story

Best thing I did was to abandon the mechanical pump, go with rear mount electric, a thick carb spacer, and built a fuel return system like the 440 / 426 cars used. Use a Wix 33040 / 41 filter which has a built in 1/4" return port.

Also some carbs are far worse. Ed AFBs are worse than Holley, although an AFB is what I ran I got mine down to "a few seconds of stumble" after a hot soak in a parking lot. Up here it gets into the 90's this summer was a hot one.

These old cars with manual fans seem to get hotter and hotter after parking them. I wonder if a guy could rig an electric fan up to the front side of the radiator to keep air flowing through it. A ten minute timer to keep the cool air flowing should make a great deal of difference. Though I don't know if you'd actually have to keep the water circulating to make this really work.

I think a fan anywhere to keep air flowing through the engine bay could help quite a bit.

I gave up on that though and installed a toggle switch going to the aftermarket electric fuel pump. I flip the switch off a few hundred feet before parking it and don't have to answer any questions about the puddle of fuel and the smell.

Hayden makes a nice fan and also sales a timer if you need one... Good Stuff, I run one in my wifes brand-X Classic....

Running an electric fan even without the water running does make a big change. Add in an electric water pump on same timer and that would help until stat closes. My Jeep has a mechanical main fan and aux electric fan. I installed toggle switch to give me full control when electric fan is on. Creeping at slows speeds on trails and higher revs (in uber low gears) on obstacles can make rigs runs hot, even with the fan covering less than half the size of the radiator it cools my truck back down a lot by the time we get all rigs through and ready to roll again. When running aux fan constant on, doesn't even really warm up on the obstacles much anymore.
The other thing that helped me a bit was hood louvers, not sure where you are planning to go on your build but that might be an option. I have heard having vents between door and wheel wells works extremely well with fan also.
Would a lower temp t-stat help maintain a cooler block temp to possibly help too? Not familiar with living in the desert so thought I would throw it out there.

MOTOR OFF is a heat sink.